The 5 C group of companies have developed DTCP/IP method that uses IP and asynchronous communications to accomplish localization determination. The IDB Forum developed a similar method for communication between source and sink devices in a 1394 network, which uses AV/C asynchronous communication and involves a sink device to cryptographically manipulate a message during round trip time measurements.
A typical 1394 includes at least one source device and at least one sink device among many devices connected to a 1394 bus. A localization process determines that the communication loop between the source device is within the network. Conventional methods (e.g., DTCP/IP), measure round trip time using software stacks, and so the majority of the time measured is really time spent in nodes of switching from one of software stack to another, rather than time data travels on the bus.